Products of thermally insulating material in hermetically sealed bags are well-known in the art, for instance so-called vacuum insulation panel (VIP).
Current VIP technology typically comprises an insulation material, e.g. formed of fumed silica, mineral fibres or other microporous material core. The core being wrapped in a flexible, gas-tight envelope and a vacuum is applied before sealing. The vacuum is essential to the panel's thermal insulating performance. If the vacuum disappears the panel loses a large proportion of its thermal properties, with the thermal conductivity reverting to that of the core material. Meaning, that all kind of piercing of the envelope due to one or more of handling damage, like e.g. cutting to size, fixing to a building substrate and damage caused by drilling of holes for wiring, shelf fixing and the like is very problematic and crucial to the panels. The before said being one of the reasons why the use of VIP technology in building construction nowadays is still not widespread. Moreover, in particular the use of mineral fibre materials has some additional drawbacks and as such these core materials would not be first choice. Thus, microporous materials would be needed which, however, are very expensive.
Another approach has earlier been proposed in providing hermetically sealing porous insulation material within sealed bags and substituting the contained air with a gas. Reference is e.g. made to U.S. Pat. No. 2,779,066, which relates to a refrigerating apparatus and more particularly to an improved arrangement for insulating the walls of such refrigerators. Provided is an improved and practical insulation in which gas having a low coefficient of thermal conductivity is used in combination with glass fibers or the like.
In WO 2012/164310 there are disclosed composite material panels comprising insulation layers comprising a solid open-cell foam panel, which may have at least one internal void therein, and wherein one or more surfaces of the panel and/or the voids are provided with an air-tight sealing coating. The internal void spaces may be evacuated or contain air or an inert gas at around atmospheric pressure.
WO 96/03555 discloses a lightweight, partially evacuated load-supporting insulation panel comprising an outer gas-impermeable envelope and an inner gas-permeable envelope. The inner envelope is filled with a mixture of coarse gas-permeable granules and fine gas permeable particles, void spaces formed within and between said granules and particles containing a gas of low thermal conductivity.
In CA 1290677 there is disclosed insulating panels which are formed from compressed particulate material impregnated with insulating gases, the combination being held in a gas tight pouch. These pouches can be placed in the insulation space of a structure where insulation is to be provided and, if desired, encapsulated in a foamed insulating material. Among the possible particulate materials is precipitated silica, while various Freon gases can be employed as the insulating gas.
Although an insulation product comprising a board of porous insulation material wrapped in a gas-impermeable foil and comprising an insulating gas is known as such, no such products have ever been introduced to the building sector since production has been a major challenge; hence there is no industrially suitable method of producing such products.